The consequences of the Little Ice Age period over peat sequestration in northern peatlands

小冰期时期对北部泥炭地泥炭固存的影响

• 批准号: 250287-2012
• 负责人: Garneau, Michelle
• 金额: $ 2.33万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=633851
• 关键词: consequences; Little; Ice; Age; period

The research program presented in this 5-years proposal follows my precedent research activities conducted over the entire Holocene period providing original data on peat initiation, peatland development and related C accumulation from different ecoregions of the northeastern canadian boreal biome. Our results present regional spatial and temporal Holocene C accumulation along with distinct seasonal patterns and confirm the role of long-term climate variations as an important driver in peatland dynamics and related C sequestration. In the international community, recent initiatives have been taken up to enhance the understanding of critical climate periods on peat accumulation such as the Neoglacial period (3000 BP), the Medieval Climate Anomaly (350-1200 BP) and the Little Ice Age (LIA) (1350-1850 AD). In northern countries, the LIA represents a critical period as it has influenced permafrost aggradation over the past centuries. Nowadays, some relict permafrost remains in the most northern regions of the open boreal forest and in the taiga while geomorphic indices in some other part of the landscape suggests its recent melting. The detailed reconstruction of the onset of this recent cold anomaly period, its impact over peat accumulation and its recent disappearance influenced by the recent warming will be used as analogs to document the consequences of the present-day arctic warming in northeastern Canada. We intend to document the impacts of external forcings such as the variations in the North Atlantic Oscillation (NAO), solar radiation and/or volcanic activities that have been identified as principal causes of this cooling. Methods such as macrofossils, testate amoebae, humification and isotopic analyses coupled with precise dating chronologies (14C and 210Pb) and age models will support the detailed reconstructions of this period characterized by cold climate disturbance and subsequent warming. Results of improved methods will also be integrated into international efforts (Europe, United, other parts of Canada) for amalgamation of various peat databases and development of outputs that will be useful for the PMIP (Paleoclimate Modelling Intercomparison Project) and PCMIP (Paleocarbon Modelling Intercomparison Project) modellers community that respond to the IPPC reports.

这个五年提案中提出的研究计划遵循了我在整个全新世时期进行的先例研究活动，提供了加拿大东北部北方生物群落不同生态区的泥炭形成、泥炭地发育和相关碳积累的原始数据。我们的结果呈现了区域空间和时间全新世碳积累以及不同的季节模式，并证实了长期气候变化作为泥炭地动态和相关碳封存的重要驱动因素的作用。国际社会最近采取了一些举措来加强对泥炭积累关键气候时期的认识，如新冰期（距今3000年）、中世纪气候异常（距今350-1200年）和小冰河期（LIA）（公元1350-1850年）。在北方国家，LIA 代表了一个关键时期，因为它影响了过去几个世纪的永久冻土退化。如今，在开阔的北方森林和针叶林的最北部地区仍然存在一些残留的永久冻土，而其他一些地区的地貌指数表明其最近正在融化。对近期寒冷异常时期的开始、其对泥炭堆积的影响以及近期变暖影响的近期消失的详细重建将被用作类比，以记录加拿大东北部当今北极变暖的后果。我们打算记录外部强迫的影响，例如北大西洋涛动（NAO）的变化、太阳辐射和/或火山活动，这些已被确定为导致这种降温的主要原因。宏观化石、睾丸变形虫、腐殖化和同位素分析等方法，加上精确的测年年表（14C和210Pb）和年龄模型，将支持对这一以寒冷气候扰动和随后变暖为特征的时期进行详细重建。改进方法的结果也将纳入国际努力（欧洲、美国、加拿大其他地区），以合并各种泥炭数据库并开发输出，这些输出将有助于响应 IPPC 报告的 PMIP（古气候模拟比对项目）和 PCMIP（古碳模拟比对项目）建模者社区。